Improvement in bridge-ladders



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ras snmilc co. moro-mms au PARK mAcs'Nm UNITED STATEs PATENT OFFICE.

PAOLO POETA, OEl MILAN, ITALY, AssIGNOE To MIOHELE UDA ANDv MAEY BELLAsoOTT UDA, OE SAME PLAOE.

IMPROVEMENT IN BRIDGE-LADDERS.

Specification forming part of Letters Patent No. l55,751, datedOctober6, 1874; application led 1 y March 25, 1874. v Y Y Bridge-Ladders orFlying Bridges; and declare the following to be a full, clear, and exactdescription thereof, as will enable others skilled in the art to whichit pertains to make and use it, reference being had to the accompanyingdrawings, which make a part of this specification. V

My invention relates to an improvement in bridges, which I term abridge-ladder or flying bridge, in contradistinction to such bridges asrequire pier-support; and consists of the combination of devices andappliances, as hereinafter specified and claimed, consisting essentiallyof a truck, to which is pivoted and 'attached the lower section of thebridgeway, to which are added other sections of the same by suitablejoining and bracing device, and the whole, so adjusted and arranged bysuitable mechanism that, by the operation of said mechanism, my devicecan be used either for the purpose of a bridge, or can be raised to anydesired angle, and made self-supporting by the system of adjustablecounterpoise-weights Vand other devices, as ,will hereinafter more fullyappear.

In the drawings', Figure 1 is a side elevation of my invention; Fig. 2,a longitudinal section of the same.

A is the bed of a truck, at the rear part of which is pivoted the lowersection B of the bridge. This section has a rigid leverarm, B1,projecting at an angle toward the rear, which bears the roller C at itsextremity. A shaft or roller, D, placed upon the truck A, in front ofthe pivot b, is provided with a gear-wheel, c, that engages with thepinion D1 on the end of the crankshaft D2. I do not, however, limitmyself to this method of operating the shaft or roller D, as anysuitable equivalent mechanism may be employed for the purpose. One ormore lines, E, pass down beneath the roller F, attached to the lower endof the descending brace F at the rear of the truck A; thence up to theroller G, and down again to the truckbed, to which they are securelyattached. E are lines passing from the extremthey are attached tosuitable winding shaftsA or rollers e2 in the forward portion of thetruckbed. The rollers or shafts e2 are provided with suitable crank orgearing device. Y is a straining-line attached to the extremityof thesecond added section of the bridgeway, passing' from thence over theroller C of the angular lever-arm B; from thence downward around thepulley F of the descending brace F', and

thence forward, where it is attached to a suitable roller or shaft, y,operating in the truck.

bed A, and operated by suitable crank or gearing arrangement. Theuprights Z upon the truck A, when in use, are suitably braced towithstand the strain put upon them. At their bases they are divided, butprovided with theV hinge z upon their rear face, and the locking devicez* upon their anterior face, so that when not in use they may beunlocked and turned backward upon the supports z2. To counteract anytendency to tip forward, the truck A is provided with suitable slidingor adjustable counterpoise-weights G, and, when necessary, the eXtra'counterpoiseweights Gr', swung upon i the bars g, which are xed andbraced to the truck A. When my bridge is ready for use, as shown in Fig.l, the brace-rods K K1 K2 K3 L, with their intermediate posts L', form arigid and steady truss-support.

rlhe construction of the various parts of my bridgeway will be readilyunderstood by reference to the drawings.

The posts L are situated at or near the ends of each section of thebridgeway, and the straining-rod K extends from the exterior end of eachto the base of the next succeeding one, while a tie-rod, K1, insections, unites the ends of all. The lever-arm B of the basesection isstrongly secured by the straining rods or bars K2 K3 L. It will be `seenthat the strains are all strains of extension, excepting those on theposts and upon the ways, which in both instances are longitudinalstrains of compresor morel extra straining-rods, O, ,extending` from thetop of the posts L to the middle portions of the way-sections, andacting in the same capacity as the rods K. The ends of the way-sectionsare provided with strapfloops b', Y

and are halved, mortised, or otherwise shaped so as to fit upon eachother, and permit the key-bar M to be inserted. Other devices foruniting the sections and the tierods may be employed; but the devicesshown are simple and effective. The truck is provided with suitablerunnin g-gear and devices for braking and fixing the carriage rigidly inany desired place. The posts L are provided at their bases and upperextremities with the spurs jl, over which are slipped the extremities ofthe connecting tie-rods and straining-rods, and are provided with thepins or keys jl for securing the same.

My invention is susceptible of a double use, viz., of a bridge, asbefore described, and of a portable signallookout. The latter may beaccomplished by unshipping the lines E and operating the shaft or rollerD. This winds the cords E upon the shaft or roller D, and, by shorteningthe distance between the rollers U and F, brings the lever-arm B downand carries the section B, with all its attached sections, upward to anydesired angle, as shown in my device for iiremens ladder, for whichpatent N o. 142,349 of the United States, dated September 2, 1873, wasgranted to me. In this condition the bridgeway is transformed into aladder, at the top of which may be fixed any suitable plat-form or cage,from which observations may be taken. I have provided on the forwardportion of. the truck-bed A the shaft l', with its line. This is to beused when the bridge is transformed into a si gnai-lookout, for thepurpose of hoisting the platform or observatory to the top ot theelevated ladder by passing the line of the shaft I upward andthroughsuitable pulley arrangement fixed to upper section of the ladder.It is also provided with suitable hooks and rests p, or other devicesfor depositing and carrying tie-rods, extra counterpoise-weights,removable braces, and other of the smaller detachable portions of thebridge, when said bridge is not in use, or is being transported from oneplace to another. When not in use all the sections of the `bridgeway,with their bracing-rods and lines,

are detached and placed upon the truck A, in which condition it will beseen that the entire structure is easily portable.

. V'lhe operation is as follows: The bridgeway is made to any desiredlength by the addition of a requisite number of sections thereto, whichare adj usted in a horizontal position. The sections are then raised bydepressing the rigid arm of the basefsection through its mechanism. Inthis elevated position the structure is moved to the bank ofthe streamto be crossed, when the bridge is lowered to the opposite bank. By myprovision I am enabled to swing my bridge to an opposite bank of adifferent altitude from that on which the truck A stands. When thebridgeway has been lowered the operating parties go out upon the saineand adjust the suspension-cords in their proper position, after whichthey are made taut by their proper rollers, and act to sufficientlysustain the bridge.

What I claim is- The combination, with a self-supporting ladder andcounterpoised portable truck, A, as described and shown, of adjustableuprights Z and adjustable suspension-cables E E', whereby said laddermay be readily transformed into a bridge, substantially as shown anddescribed.

In testimony that I claim the foregoing I have hereunto set my hand andseal this 6th day of March, 1874.

PAOLO PORTA. [1.. s]

Witnesses:

BENJ. FRAILLE, Prof. OSCAR CoconDA.

